Today many different types of plate heat exchangers exist and are employed in various applications depending on their type. Generally, a heat exchanger has a number of heat transfer plates that are joined to each other to form a plate stack. In the plate stack there are alternating first and second flow paths in between the plates. A first fluid flows in the first flow path and a second fluid flows in the second flow path. As such flow goes on and when there is a temperature difference between the fluids, heat is transferred from the warmer fluid to the colder fluid.
The design of the heat transfer plates is important for providing efficient transfer of heat between the fluids. The plates must also be durable and should withstand various stresses that may occur, for example due to pressure variations and temperature differences.
The heat transfer plate has typically a dedicated heat transfer area with a pattern that is pressed into the plate. Often the plate has also a fluid distribution area with a dedicated pattern that distributes fluid from an inlet port, or edge, towards the heat transfer area. A corresponding fluid collection area collects fluid that has passed over heat transfer area and leads it towards an outlet port, or edge. The pattern for the fluid distribution and fluid collection areas is often pressed into the plate simultaneously with pressing of the pattern for the heat transfer area.
However, it is not always desired to have the fluid distributing and/or fluid collection pattern on the same plate as the heat transfer pattern. Special types of heat exchangers are then employed, such as the type where individual fluid distribution plates and individual fluid collection plates are located in between base plates that are joined to each other. Between each pair of base plates a fluid distribution plate is then located at one end, and a fluid collection plate is located at another end. Between the ends the base plates have heat transfer areas. This type of arrangement provides e.g. the possibility to accomplish cost efficient manufacturing of large heat exchangers, while still ensuring efficient distribution of fluid to the heat transfer area and subsequent collection of the fluid after it has passed the heat transfer area.
A number of embodiments of heat exchangers with individual fluid distribution and fluid collection plates have been disclosed. In comparison to several other types of plate heat exchangers, the heat exchanger allows the use of large heat transfer plates and provides efficient transfer of heat while still being durable. However, it is estimated that heat exchangers with individual fluid distribution and fluid collection plates may be improved in respect of their capability efficiently distributing fluid to their central heat transfer sections.